1. Field of the Invention
The present invention relates to a lens protection mechanism for protecting an optical lens system and a camera equipped with the lens protection mechanism.
2. Description of Related Art
Portable compact cameras such as a conventional compact still camera for use with a silver film and a digital camera are generally equipped with lens protection mechanisms installed at a front end of a lens barrel for the purpose of protecting an objective lens from getting dirt and damage while the camera is unused.
One of such lens protection mechanisms disclosed in, for example, Japanese Patent Publication No. 2612128 comprises a protection cover, bias means such as a biasing spring for biasing the protection cover toward an uncovering or open position, cover closing means for forcing the protection cover to a covering or closed position and activation means for activating the bias means and the cover closing means in cooperation with each other. The activation means is operationally disconnected from the cover closing means to allow the protection cover to be forced to the open position by the bias means when a collapsible lens barrel is extended and, on the other hand, is operationally linked with the cover closing means to force the protection cover to the closed position against the bias means when the collapsible lens barrel is retracted.
Another lens protection mechanism disclosed in, for example, Japanese Unexamined Patent Publication No. 1-248144 comprises a lens barrier member and an operating ring member. While the camera is put to nonuse, the lens protection mechanism brings the operating ring member into engagement with a latch member forming part of the camera body and simultaneously maintains the lens barrier member in a covering or closed position by means of a link spring operationally linking the lens barrier member with the operating ring member together. On the other hand, when the camera is put to use, the operating ring member is released from the latch member to allow a tension spring linking the operating ring member with the camera body to force the operating ring member to rotate so as thereby to bring the lens barrier member into an uncovered or open position
Recent marked development of cameras presses a demand for a more compact configuration and, in consequence, a strong demand for a downsized lens protection mechanism installed in the compact camera as well as a demand for reductions in manufacturing cost. Since the prior art lens protection mechanisms exemplified above are accompanied by a mechanisms adapted to always force the lens cover member toward the closed position against the bias spring operative to bias the lens cover member toward the open position, it is essential for the lens protection mechanism to include a bias spring or a bias structure for forcing the lens cover member with bias force sufficiently stronger than the bias spring. This is one of undesirable factors standing in the way of making the lens protection mechanism compact and reducing the manufacturing cost of the lens protection mechanism.